(1) Field of the Invention:
The present invention relates to a device for fitting a mechanical working tool to a machine.
(2) Description of the Prior Art:
Conventionally a device illustrated in FIG. 1 is employed to fit a tool to the spindle of a machine. Namely, a tool such as a drill 1' is fixed to the tool-fitting body 4' by turning the tightening collar 3' through the collet 2' which is circumferentially split into a number of pieces; the tool-fitting body 4' holding the tool is inserted into the hole or bore 5a' bored in the spindle 5'; and then the tool is fixed to the spindle 5' with the tightening bolt 6' so as not to be pulled out.
In such a conventional device, for the purpose of preventing rotation between the tool-fitting body 4' and the spindle 5' due to the torque acting on the drill 1' in time or working, a key groove 5b' is provided axially on the spindle 5' and a key 7' provided on the outside of the tool-fitting body 4' engages said groove 5b'. Meanwhile, for the purpose of preventing an axial sliding of the tool-fitting body 4' relative to the spindle 5' or pull-out of body 4', a screw hole is bored on the side surface of the spindle 5' at a position beyond the bearing 8' and the oil seal 9' of the machine; a tightening bolt 6' is screwed into said screw hole and thus the tip of the bolt is pressed against the outside of the tool-fitting body 4'.
Such a construction has the drawback of taking considerable time and skill for tightening the bolt 6' and engaging the key 7' in fitting the tool-fitting body 4' holding a drill 1' to the spindle 5' of the machine. Particularly when a number of tools are to be fitted to the machine at the same time, the time required for fitting the tools makes one of the important factors impeding efficient work. Since the spindle 5' has to be provided with the key groove 5b', the part of the spindle 5' where hole is to be bored must have its thickness that correspondingly increased, which results in widening the distance to the adjacent tool and making it impossible to perform a simultaneous working of a site narrower than this distance. Thus the workable range of the machine is limited. Moreover, the distance from the outer end of the bearing 8' to hold the spindle 5' to the tip of the drill, i.e., the overhang B has to be extended to permit installation of the tightening bolt 6', with the result that the tip of the tool becomes liable to oscillate.